a, This is an extension of the data shown in Fig. 3k, including two younger ages of mice. Circulating SASP factors were measured by ELISA (n = 3 for 2–3-month-old, n = 4 for 5-month-old, n = 5–7 for 8–11-month-old, n = 7 for 24-month-old) (see Supplementary Table 3 for sample size details). Data are mean ± s.d. *P < 0.05, ∞P < 0.01, ∇P < 0.001, #P < 0.0001, two-way ANOVA with Tukey’s test. b, Haematoxylin and eosin sections of brain, kidney and liver from 17-month-old Vav-iCre+/−;Ercc1−/fl and littermate controls (n = 5 mice per group) were scored for age-associated histopathological lesions using the Geropathology Grading Platform to generate a composite lesion score for each organ (CLS). Data are mean ± s.d. P values (not significant) were determined by two-tailed unpaired Student’s t-test.